1. Field of the Invention
The present invention relates to one first part comprising of one first portion which extends along an axis X, the first part being laterally bordered by a lateral surface and presenting a proximal portion, which is extended by an intermediate portion which is extended by a distal tip, the extremity of which is one first surface, this first surface is meant to be welded/soldered by friction on one second surface of a second portion of a second part.
2. Description of the Related Art
The welding/soldering by friction is a procedure of welding which consists of assembling two parts by putting these two parts in movement in relation to one another and by supporting them against each other in such a way that one surface of the first part rubs on the surface of the second part. The rubbing of these surfaces against each other thus generates sufficient heat to heat the area of each part which is adjacent to the surfaces in contact which brings them to a malleable state.
These areas are thus capable to get deformed and solder together. After stopping the movement of one part relative to another, and the cooling of the two parts, these are thus soldered together.
During this welding, the regions adjacent to the contacting surfaces, which are in the malleable state, are deformed by discharging of the material at the extremities of the contact zone. This expelled material forms beads.
This is illustrated in FIGS. 4A and 4B, which represent the prior art.
A first part 1100 comprises of one first portion 1120 which is an excrescence of the first part 1100 and extending along an axis X. This first portion 1120 is bordered laterally by one lateral surface 1130 and presenting one a proximal portion 1122, which extends through intermediate portion 1124 that extends through a distal portion 1126. The extremity of this distal portion 1126 is one first surface 11136.
A second part 1200 includes one second portion 1220 which is an excrescence of the second part 1200 and which extends along an axis Y. This second portion 1220 is bordered laterally by one lateral surface 1230 and presents one proximal portion 1222, which extends through intermediate portion 1224 that extends through a distal portion 1226. The extremity of this distal portion 1226 is one second surface 1236.
In the welding procedure according to the prior art, one places in the first part 1100 in motion in relation to the second part 1200, and one approaches the first surface 1136 until they are in contact.
In the case illustrated in FIGS. 4A and 4B, the first portion 1100 is a tube axis of symmetry of which is the X axis, and the second portion 1120 is a tube of which the axis of symmetry is the Y axis, these two tubes are identical with the possible exception of their lengths according to the axis X and axis Y.
Considering the symmetry with respect to axes X and Y, only one half of parts is shown in longitudinal section.
The lateral surface 1130 of the first portion 1120 is thus comprised of a interior surface 1131 (which is a cylindrical surface of diameter equal to the interior diameter Di) and an external surface 1132 (which is a cylindrical surface of diameter equal to the diameter from the exterior De).
The lateral surface 1130 of the first portion 1220 is thus comprised of an interior surface 1231 (which is a cylindrical surface of diameter equal to the interior diameter Di) and an external surface 1232 (which is a cylindrical surface of diameter equal to the exterior diameter De).
The first lateral surface 1136 and the second surface 1236 are thus each an annular band with the inner diameter Di and the same exterior diameter De.
The first member 1100 is put into rotation around the X axis by means of a drive system (not shown). Once an angular speed of rotation is attained, the first part 1100 is separated from the drive system (the first part 1100 is thus in free rotation), then the first surface 1136 is put in contact and pressed against the second surface 1236 with a determined force, in such a way that these two surfaces overlap. The X axis and Y axis are merged. Likewise, the inner surface 1131 of the first portion 1120 on the inner surface 1231 of the second portion 1220 are aligned and form part of the same inner surface of a circular tube with a diameter Di. Similarly, the outer surface 1132 of first portion 1120 and the outer surface 1232 of the second portion are aligned and are part of the same surface of a circular tube diameter De.
The heat generated by the rubbing of the first surface 1136 and of the second surface 1236 makes the distal portion 1126 of the first part 1100 and the distal portion 1226 of the second part 1200 malleable which welds/solders by discharging the material at the extremities of their contact surface. This expelled material forms an interior bead 1310 on inner surface 1131 of first portion 1120 and inner surface 1231 of the second portion 1220, and an external 1320 on the outer surface 1132 of first portion 1120 and the inner surface 1232 of the second portion 1220.
4A shows the two parts (1100, 1200) just prior to contact.
4B shows the two parts (1100, 1200) after welding.
It is noted in FIG. 4B at the end of the welding process the flanges (1310, 1320) exceeds and are raised relative to the lateral surface 1130 of the first part 1100 and at the lateral surface 1230 of the second part 1200.
In practice, these (1310, 1320) should be further smoothened by machining.
One observes, for a lot of parts described here-above and theoretically identical, which are welded by friction according to the method described above, a significant dispersion in the volume of the beads (the dispersion is defined as the difference between the maximum value and the minimum value). This dispersion is due to the geometric tolerances of parts, tolerances in the properties of the materials constituting the parts, tolerances in the operating conditions of the welding process in general.
As a result, it is impossible to accurately predict the volume of the beads and it is therefore necessary to provide for each part a larger distal portion (1126, 1226), since the beads (1310, 1320) are formed by the deformation of the distal portions.
It results in an utilisation of a material in the development of parts (amount of material consumed during welding, called “material consumption”) more than necessary, which is expensive and undesirable. In addition, the superfluous material (thickness superfluous of certain parts) must later be removed, resulting in additional costs.